Indoor and outdoor illuminated signs are known devices widely used all over the world for orientation, advertising and other purposes, and are typically installed in public places where a large number of people can see them. Many signs need to be visible at night and this is often accomplished by internally illuminating the information (indicia) presented on a sign panel. Various techniques are used to construct a sign device with substantially uniform illumination of the indicia.
Most of the conventional devices of the kind specified utilize fluorescent tubes or incandescent lamps as light sources, which are characterized by up to a 360°-spread of generated light. A light box utilizing such a light source is typically equipped with reflectors and diffusers so as to prevent the creation of “hot spots” and regions of excessively greater than average illumination, and to obtain uniform distribution of light impinging onto the inner surface of the front panel. This results in a drastic reduction in the amount of light emerging from the front, indicia-containing panel of the device towards the viewer.
Internally illuminated sign devices utilizing light emitting diodes (LEDs) as light sources have been developed, and are disclosed, for example, in U.S. Pat. Nos. 5,105,568; 5,539,623; 5,388,357; 5,729,925; and 4,952,023. According to U.S. Pat. No. 5,105,568, a plurality of LEDs is aligned along all the parts (letters) of textual information, and high reflective elements are provided on selective areas of the inner surface of the sign panel. According to U.S. Pat. No. 4,952,023, reflectors are used in the optical path of light propagating inside the light box towards the sign panel.
Illuminated house signs are generally installed on the outside of the home to show a family name and/or house number and street name. Such signs need to be reasonably priced and suitable for mass production. Such a sign device also needs to be custom-made so as to carry a unique family name and/or a specific house number. Conventionally, this is achieved by making an illuminating box wide enough to encompass several letters and/or numerals, and using a mask, which is supplied in sufficient duplicates of letters and/or numerals to create the specific indicia (address and/or name). When in operation, the mask covers the illuminating box to create indicia showing the desired house number, address or family name.